Referring to FIG. 1, according to a process for manufacturing a semiconductor package, a wire bonding process is widely applied to form an electrical connection between a pad 32 of a chip 10 and a finger 34 of a substrate 12 by using a bonding wire 20. Such a wire bonding process is mainly based on gold (Au) wires, but copper (Cu) wires have an advantage of low cost.
Referring to FIGS. 2 to 6, they depict a conventional forward wire bonding process. Referring to FIG. 2, a bonding wire 20 is provided by a capillary 18 of a wire bonding machine 16. One end 23 of the bonding wire 20 is bonded to a pad 32 of a chip 10 so as to form a first bond 21. Referring to FIG. 3, the capillary 18 is upward moved to a predetermined height. Referring to FIG. 4, the bonding wire 20 is curved by the capillary 18. The necessary length of the bonding wire 20 is automatically provided by the wire bonding machine 16. Referring to FIG. 5, the other end 25 of the bonding wire 20 is bonded to a finger 34 of a substrate 12 so as to form a second bond 26. Referring to FIG. 6, the rest part 20′ of the bonding wire 20 is separated from the second bond 26 so as to form the conventional wire bonding structure.
Referring to FIGS. 7 to 11, they depict a conventional reverse wire bonding process. Referring to FIG. 7, a bonding wire 20 is provided by a capillary 18 of a wire bonding machine 16. One end 23 of the bonding wire 20 is bonded to a finger 34 of a substrate 12 so as to form a first bond 21. Referring to FIG. 8, the capillary 18 is upward moved to a predetermined height. Referring to FIG. 9, the bonding wire 20 is curved by the capillary 18. The necessary length of the bonding wire 20 is automatically provided by the wire bonding machine 16. Referring to FIG. 10, the other end 25 of the bonding wire 20 is bonded to a pad 32 of a chip 10 so as form a second bond 26. Referring to FIG. 11, the rest part 20′ of the bonding wire 20 is separated from the second bond 26 so as to form the conventional wire bonding structure.
Referring to FIG. 12, it depicts a plan schematic view of the conventional forward or reverse wire bonding structure. There are a lot of bonding wires 20, which are tightly arranged in order, and the projection portion of the bonding wire 20 on the substrate 12 is a straight line. Referring to FIG. 13, according to the conventional forward or reverse wire bonding structure, possibly there is a problem of wire sweep so as to further cause a short circuit between adjacent two of bonding wires because of the shock of a mold flow of a molding compound when the molding compound is subsequently formed.
Accordingly, there exists a need for a wire bonding structure of a semiconductor package capable of solving the above-mentioned problems.